> And if they can do their jobs remotely, why can't an equally skilled engineer in a country with a cost of living 1/10th of the "rich countries" do the same?
I'm an American expat and one of the things that I quickly discovered when I left and started traveling is that skilled engineers (and designers, etc.) in countries with significantly lower costs end up figuring out how much they're worth to employers/clients in richer countries. When they do and they have enough of a track record to prove their worth, their rates go up.
So if you think you're going to take your freelance developer in the US who charges $150/hour and replace him with an equally skilled freelance web developer in, say, Brazil for $15/hour, good luck. Any such developer in the Brazil will eventually discover that he's able to command much more. Except in a few rare instances it won't be $150/hour, but when you factor in time zones, cultural differences and language, there is far less of a difference in cost than you'd think.
Anecdotally, I have a few friends that run companies in the US that have expanded their hiring to consider remote candidates outside of the US and Canada and they still struggle to find suitable candidates even though the rates they're offering are based on qualifications, not location. In other words, they're willing to pay $100+/hour to the right people no matter where they live. Good people are in demand everywhere, and they know it.